Fuel feeding means



July 24, 1962 w, D. NUTTEN ETAL 3,045,605

FUEL. FEEDING MEANS Filed Sept. 15, 1958" 2 Sheets-Sheet 1 July 24, 1962 w. D. NUTTEN ETAL 3,045,605

FUEL FEEDING MEANS Filed sept. l15, 1958 z sheets-sheet 2 TNS/5N T0125: WARREN Z7. NUT TEN. I IEE BMM/m7 L. PHILLIPS.

Patented July 24, 1962 3,045,605 FUEL FEEDING MEANS Warren D. Nutten, Erie, Mich., and Bernard C. Phillips, Toledo, Ohio, assignors to The Tillotson Manufacturing Company, Toledo, Ohio, a corporation of Ohio Filed Sept. 15, 1958, Ser. No. 760,939 9 Claims. (Cl. 10S-150) This invention relates to -apparatus for delivering fuel to a charge forming device which is adapted to supply a combustible mixture of fuel and air to an internal combustion engine, the invention more especially relating to a diaphragm type pumping means.

Internal combustion engines of two-cycle type have come into extensive use in powering small boats, particularly of the outboard type, lawn mowers, chain saws, portable impacting devices, portable drill equipment 4and for industrial uses. A fuel feeding means or pump of the diaphragm type actuated by varying iluid pressure may 'be utilized either as an independent pump unit or as a component associated with a charge forming device for supplying fuel to the charge forming device or carburetor, the latter being utilized to deliver a combustible mixture of fuel and -air -to the engine.

Pumps or fuel feeding means for such purposes employ a flexible diaphragm pumping element arranged to form a wall of a pumping chamber and a Wall of a fuel feeding chamber provided respectively at opposite sides of the `diaphragm with the pumping cham-ber in communication with a source of varying fluid pressure as a motivating force for actuating the diaphragm.

When pumps of this character are utilized with a charge forming device associated with a two-cycle engine, the pumping lchamber of the fuel Ifeeding means is connected with the crankcase of the engine and the varying pressure in the crankcase utilized to actuate or vibrate the flexible diaphragm to obtain a pumping action. The pumping means may be actuated from any other source of variable pressure. A type of diaphragm pump of this character is illustrated in United States Patent No. 2,796,838 granted to Bernard C. Phillips on June 25, 1957.

The arrangement shown in this patent embodies a ilexible diaphragm having valves cooperable with the inlet and outlet ports of the pump formed as integral tongues or aps on the diaphragm. In valve closing position, the aps or tongues yforming the valves are arranged to lie against a flat or planar surface, a member adjacent the ilap and opposite the valve ports being provided with recesses to accommodate opening movement of the valves. A gasket may or may not be used between the diaphragm and the adjacent member of the pump containing the recesses accommodating opening movements of the valves.

In the assembly of the components of the pump, the members at opposite sides of the pumping diaphragm are drawn into tight engagement with the diaphragm and the gasket, if one is employed, to provide a fluid tight construction. In such arrangement the valve tongues or flaps, when in closed position, are intended to lie coincident with a at or planar portion of the adjacent member, but in many instances it has Ibeen -found that the iiap does not seat properly but is stressed or Idistorted away from the seat at a minute vangle so that the port is not closed when the valve is intended to be in port-closing position.

It has been found that the pressure exerted upon the diaphragm or upon the gasket and diaphragm by the securing screws which hold these components in assembled relation causes a flexure or distortion of the valve flap or tongue preventing the valve from -attaining a fully closed position, and in operation the valves do not function properly, resulting in a partial or complete failure of the pumping means to feed yfuel to a charge forming device.

In the utilization of the variable pressure in the crankcase of a two-cycle engine as a medium for actuating the pumping diaphragm, the speed of the engine may be 6000 r.p.m. or more resulting in movements of the diaphragm and valves of a corresponding number of pumping cycles and valve movements in the pumping means. The ilap valves or tongues must seat properly at each pumping movement of the diaphragm or leakage results, a condition which is aggravated if the valves are stressed or biased away from seating positions.

The present invention embraces a pumping means of the diaphragm type embodying a configuration adjacent a flap valve of the pumping diaphragm whereby the assembly of the diaphragm and adjacentcomponents of the pumping means do not affect the normal or valve closing position of a ap type valve whereby proper valve closing operation of the valve means is attained under all conditions of operation.

An object of the invention is the provision of va relief area or surface of the member adjacent the zone of hinge movement or flexure of a flap valve in a diaphragm pump of this character which eliminates any tendency of the valve to be flexed or distorted from its normal or closed position when the components of the pump are held in assembled relation.

Another object of the invention is the provision of a `diaphragm pump having flap valves formed integrally with the diaphragm wherein a progressive or gradually receding relief or ramp surface is provided adjacent the hinge region of the ap valve functioning to avoid transmission of compressive stresses on the diaphragm to the flap valve portions thereof.

Further objects and advantages are within the scope of this invention such as rel-ate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent lfrom a consideration of the specification Yand drawing of a form of the invention, which may `be preferred, in which:

FIGURE l is a side elevational view of a charge Iforming device or carburetor in combination with a diaphragm pumping means embodying the invention, the pumping means being shown in section;

FIGURE 2 is a transverse sectional view of the charge forming apparatus illustrated in FIGURE 1, the pumping means being shown in elevation;

FIGURE 3 is a plan view of one of the components of the pump provided with the cavity forming ythe pumping chamber and the recesses accommodating the opening movements of llap valves;

FIGURE 4 is a plan view of the component disposed at the opposite side of the diaphragm and provided with a cavity adapted to receive the liquid fuel;

FIGURE 5 is a sectional view taken substantially on the line 5-5 of FIGURE 1;

FIGURE 6 is a plan view of the pumping element or diaphragm;

FIGURE 7 is an enlarged fragmentary detail plan view of one of the pump components and a valve region of the diaphragm superposed thereon;

FIGURE 8 is a sectional view taken substantially on the line 8--8 of FIGURE 7 illustrating one form of valve relief surface;

FIGURE 9 is a View similar to FIGURE 8 showing a modified form of valve relief surface;

FIGURE l0 is a fragmentary sectional view taken substantially on the line 10-10 of yFIGURE 3;

FIGURE 1l is a fragmentary detail view taken substantially on the line 11-11 of FIGURE 3;

FIGURE l2 is an enlarged detail sectional View taken substantially on the line 12.-12 of FIGURE 4, and

FIGURE 13 is an enlarged detail sectional view taken substantially on the line 13-13 of FIGURE 4.

While the fuel feeding or pumping apparatus of the present invention is -illustrated as particularly adapted for pumping liquid fuel to a charge forming device of an internal combustion engine of the so-called two-cycle type, it is to be understood that the pumping means of the invention may be used for pumping fuel to other types of charge forming apparatus or for any purpose wherein a diaphragm type pump may be employed.

It is to be understood that while a preferred form of pumping means of the invention is illustrated as forming a component of a charge forming device or carburetor, the pumping arrangement may be an independent unit connected between the source of fuel supply and the fuel inlet of a charge forming device or apparatus and is especially suited for supplying liquid fuel to a charge forming device which is adaptable for use in any angular position or in an inverted position.

Referring to the drawings in detail and initially to FIG- URES 1 and 2, there is illustrated =a charge forming device or carburetor combined with a fuel feed feeding means or fuel pump of the diaphragm type embodying the invention. The charge forming device or carburetor illustrated is of the diaphragm controlled type and is constructed with a minimum fuel lift distance whereby the fuel may be readily delivered into a mixing passage to be therein mixed with air and the resulting combustible mixture delivered into the crankcase of a two-cycle internal combustion engine by reason of the aspirating effect of varying pressures in the engine crankcase.

The pumping chamber of the pumping means is connected by a channel system formed in the carburetor body with the crankcase of lthe engine whereby separate connecting means between the pumping chamber and crankcase is avoided. A separate means or tube between the pumping chamber and crankcase may be used where the pumping means is independent of or spaced remotely from the charge forming apparatus.

The charge forming device or carburetor illustrated is inclusive of a body formed with a mixing passage 12 which includes a venturi 14 into which fuel is delivered from an outlet or nozzle for admixing'with air admitted through an air inlet 16 of the mixing passage. A disctype valve 18 is mounted upon an operating shaft 19' and is disposed in the air inlet end 16 and functioning as a choke valve for controlling the admission of air into the mixing passage, the valve being manipulated by an arm 20 secured upon a portion of the shaft 19` extending exteriorly of the body 10.

A disc-type valve 22 mounted upon a shaft 23 forms a throttle valve for regulating or controlling the llow of fuel and air mixture into the crankcase of a two-cycle engine (not shown). The body 10 is provided with a flange 24 adapted to be secured to the engine crankcase or other component to which the combustible mixture is to be delivered. The flange 24 may be secured to the crankcase by suitable bolts (not shown). The carburetor body 10 is formed with a fuel chamber or reservoir 28, one wall of which is formed by a flexible diaphragm 30, a gasket 37 being disposed between the carburetor body 10 and the diaphragm.

The diaphragm 30 may be fashioned of relatively thin, highly flexible material such as nylon cloth rendered impervious by impregnation with a resinous material which is resistant to the deleterious effects of hydrocarbon fuels. The diaphragm is preferably fashioned with one or more annular convolutions 34 to facilitate flexure or movement of the diaphragm. The fuel chamber 28 is unvented to the atmosphere so that the diaphragm 30 is responsive to the aspiration or reduced pressure in the mixing passage controlling fuel flow from the pumping means to the reservoir or chamber 28.

The means associated with the diaphragm 30 for controlling fuel llow from the fluid receiving chamber 40 of the pumping means into the reservoir or chamber 28 in the carburetor is particularly illustrated in FIGURE 2. The body of the carburetor is provided with a threaded bore adapted to accommodate a fitting or valve guiding means 42 in which a valve member 44 is slidably disposed. The upper extremity 46 of the valve member 44 is tapered or cone-shaped and adapted to project into an opening or port formed in a valve seat 48, the latter being fashioned of neoprene (chloroprene rubber) or other suitable material.

The port in the valve seat 48 is in communication by means of ducts 50, 51 and 52, formed in the carburetor body 10, duct 53 formed in the pump component 32 and ducts 54 and 55 formed in the pump component 56, with the fuel receiving chamber 40 of the pumping means.

The position of the fuel inlet valve member 44 is controlled by the relative position of the diaphragm 30 under the influence of the aspiration or reduced pressure in the mixing passage 12. Pivotally supported upon a pin 58 in a recess 60 formed in the carburetor body is a lever 62, one `arm of the lever being in engagement with the lower end of the valve member 44, the other arm of the lever being in contact with a headed member 64 which extends through the diaphragm and has a portion swaged into engagement with a reinforcing disc 65.

A metal disc 66 is coincident with the upper surface of the diaphragm and forms an ladded reinforcement. An expansive 4coil spring 68 in engagement with the lever 62 normally exerts `a slight pressure biasing the valve member 44 to seat the valve portion 46 in the seat member 48. When no mixture is being delivered from the mixing passage, atmospheric pressure exists in the reservoir or fuel chamber 28 and the pressure of the spring 68 maintains the valve portion 46 in closed position so that no fuel is :admitted into the chamber 28.

However, when the engine with which the charge forming device is utilized is in operation, the aspiration or subatmospheric pressure in the mixing passage is effective through a fuel discharge orice or outlet 15 between the chamber 28 and the mixing passage to influence the diaphragm 30 to be flexed upwardly against the pressure of the spring 68 swinging the lever 62 in a counterclockwise direction, as viewed in FIGURE 2, and lowering the valve 46 away from its seat so that fuel may flow from the chamber 40 in the pumping means into the carburetor chamber 28 thence into the mixing passage.

The rate of delivery of fuel past the fuel inlet valve 46 is thus determined by the amplitude of reduced pressure in the chamber 28 affecting the position of the diaphragm 30. The space 31 formed as a circular recess in the upper portion of the pump member 32, to provide for flexing movements of the diaphragm, is vented to the atmosphere by a duct 313 and a radial channel 35 shown in FIG- URE l1.

The pumping means of the invention is inclusive of two generally disc-like members 32 and 56 with a pumping diaphragm 72 disposed between these members, as shown in FIGURES l, 2 and 8, which are secured in assembled relation and to the carburetor body by screws 57 which are spaced circumferentially as shown in FIGURE 5. The diaphragm 72 and the members or components 32 and 56 of the pumping means are of generally circular configuration, as shown in FIGURES 4, 5 and 7. The diaphragm 72 of the pumping means is illustrated in FIGURE 6.

The diaphragm is formed with cutaway portions 74 of such configuration as to form flap valves or tongues 75 and 76 which are integral with the diaphragm material and are adapted for hinging or pivotal movement about the regions indicated at 78. The member 32 is fashioned with a concave portion or cavity 80 which with the diaphragm 72 forms a pumping chamber. Formed radially from the central region of the chamber or cavity 80 is a channel 82 which is in communication With a duct or channel 84. As shown in FIGURE l, the channel 84 registers with a channel 85 formed in the carburetor body 10.

The flange 24 of the carburetor body is formed with a channel 87 which is in communication with channel 85 and is adapted to establish communication with the crankcase of an engine with which the carburetor and pump may be used so that the varying pressure or pressure pulsations in the crankcase are communicated to the pumping chamber 80 and vibrate or flex the diaphragm to establish a pumping action in the fuel receiving chamber 40. The surface l86 of the disc-like member 32 is fiat to accommodate a gasket 88 of circular shape and having cutaway portions adjacent the pumping chamber, the ports or passages and the flap valves 75 and 76 to accommodate Opening movements of the flap Valves.

The substantially circular component 56 of the pump, shown in FIGURE 5,is provided with a concave recess or cavity 40 which with the diaphragm 72 provides a fuel receiving chamber. Formed in a Wall of the cavity or chamber 40 is a recess or channel 90v which is in cornmunication with a duct 92 which in turn is in communication with a port 94. Also arranged in the disc-like member 56 is a duct or passage 96 for establishing a channel through which fuel is admitted from a chamber 97 formed in member 56 to a region under the inlet valve 76, past the inlet valve 76 and through the duct 94 and passages 92 and 90 into the chamber 40.

As shown in FIGURES l and 13, the member 56 is formed with a central boss portion 98 provided with a shoulder 99 which forms a stop means for positioning a filter medium or screen 100 through which the fuel is filtered before it is admitted into the region or chamber 97 above the strainer 100. The component 56 is formed with a circular recess 101 arranged to receive the peripheral edge zone of the fuel filter or strainer 100. A closure member 102 of circular shape is fitted into the recess 101 for securing the filter 100 in position, a gasket 104 being provided adjacent the strainer 100 to form a fluid tight seal. A securing bolt 106 is threaded into a bore formed in the boss portion 98 for securing the closure member 102 in fixed relation with the member 56. The closure member 102 is integrally formed with a tubular projection 108 which is adapted to accommodate a flexible tube 110 adapted to be connected with a fuel tank or other supply of liquid fuel. The passage or duct 112 in the projection 108 opens into a chamber 114 provided by the curved shape of the closure member 102 beneath the strainer or tilter 100.

The member 32 is formed with recesses 116 and 118 shown in FIGURE 3 which, in assembly with the diaphragm 72, are disposed respectively above the outlet fiap valve 75 and the inlet flap valve 76, the arrangement of the recess 116 and flap valve 75 being shown in detail in FIGURES 7 and 8. As shown in FIGURE 8, the passage 92 connected with a port 94 formed in member 56 conveys fuel from the fuel receiving chamber 40 to the port region adjacent the flap valve 75. Each of the'recesses 116 and 118, which accommodate opening movement of the ap valves are formed with bottom surfaces 124 which are of fiat or planar shape as shown in FIGURE 8.

With particular reference to FIGURES 3 and 8, it will be seen that the bottom surface 124 of each of the recesses 116 and 118 is joined with the flat or planar surface 86 of member 32 by an inclined or angularly arranged ramp or surface 128 and that the juncture of each inclined surface with the flat or planar surface 86 of member 32, indicated at 130 in FIGURE 3 is adjacent the hinge region 78 of each of the flap valves 75 and 76.

The region 119 of the gasket 88 adjacent each Hap valve overhangs or extends over a portion of the ramp surface as shown in FIGURE 8. When the components of the pump are in assembled relation as shown in FIGURES 1, 2 and 8 and the screws 57 are drawn up, the regions of the gasket 88 and diaphragm adjacent the planar surfaces 86 and 87 of the members 32 and 56 are under compression stresses. The relief ramps facilitate the gradual or progressive expansion of the overhanging regions of the gasket adjacent the hinge zones 78 of the flap valves, the expansion of one region 119 of the gasket adjacent the liap valve 75 being shown in FIGURE 7. Thus the inclined or ramp surfaces serve to progressively diminish or relieve the compressive pressure on the hinge regions of the flap valves.

By providing the angular or inclined relief surfaces 128, the compressive stresses of assembly on the gasket and diaphragm do not affect the position of the liap valves 75 and 76, so that such valves normally remain in closed position.

It has been found that the relief surfaces 128 are essential to assure that the flap valves normally remain in closed position when the pump is not in operation and to assure proper closing of the valves during pumping operations to attain satisfactory operation of the pump.

It has also -been lfound that an inclination of the surfaces 128 to the planar surface 86 of about fifteen degrees as indicated at A provides a satisfactory relief ramp. An open position of the valve 75 is indicated in broken lines in FIGURE 8.

The arrangement of flap valve 76 and recess 118 is substantially the same as that of valve 75 and recess 116 shown in FIGURE 8.

The operation of the pump construction of the invention for feeding fuel to the charge forming device shown in FIGURES 1 and 2 or to any other instrumentality is as follows: The pumping chamber is in communication with a source of varying fluid pressure for causing liexure or reciprocation of the region of the diaphragm 72 registering with the cavities or chambers 40 and 80 to establish a pumping action. In the embodiment illustrated, the channels or passages 82, 84 and 87 establish communication of the pumping chamber 80 through the carburetor flange 24 with an opening in the crankcase wall of a two-cycle engine whereby the varying pressure in the engine crankcase is utilized as the pumping force. It is to be understood that the chamber 80 may, however, be connected with any source of fluid pressure.

Assuming that the fuel is delivered through the orifice 15 from the fuel chamber 28 in the carburetor into the mixing passage 12, the fuel control diaphragm 30 is elevated due to the aspiration or reduced pressure in the mixing passage effective in the fuel chamber 28 of the carburetor to swing the lever 62 in a counterclockwise direction, as viewed in FIGURE 2, permitting the valve member 44 to move away from the valve seat 48 to permit fuel to liow from the fuel receiving chamber 40 -of the pump through the channels 53, 52, 51 and 50 into the carburetor fuel chamber 28.

The vibration or flexure of the portion of the pump diaphragm 72 adjacent the chambers 40 and 80 causes fuel to Ibe drawn from the chamber 114 through the strainer 100, through the chamber or region 97 and passage 96, past the valve 76 through the channels 94 and 92 into the fuel receiving chamber 40. Fuel flows into the chamber 40 upon a suction stroke of the diaphragm 72 and upon a pressure stroke of the diaphragm, the fuel from chamber 40 flows through channel 55 and port 54 past the outlet llap valve 75 thence through the recess 116 and passages 53, 52, 51 and 50 into the carburetor fuel chamber 28 to replace the fuel delivered into the mixing passage 12.

FIGURE 9 is illustrative of a modified configuration of ramp or relief surface for a flap valve of the diaphragm. In FIGURE 9, the pump members or components 32 and 56 are of the same character as the corresponding members shown in FIGURE 8. The member 32 is formed with a recess 116 having a fiat bottom surface 124', the recess 116 accommodating opening movement of the flap valve 75 formed on the diaphragm 72. The bottom surface T124 of the recess H6' is joined to the planar surface S6 of member 32 by a curved transition or ramp surface 140. In this form of construction, the ramp surface 14) is of curved configuration, preferably generated as a radius about a point directly above the hinge region 78' of the ap valve 75. Thus, the curved ramp or ramp surface 140 provides a gradually receding surface region from the iiap valve providing for the gradual expansion of region 119 of the gasket 88 adjacent the flap valve 75' so as to prevent the compressive stresses exerted upon the gasket and diaphragm by the securing means 57 from distorting the flap valve 75. It is to be understood that the curved ramp surface 140 may be utilized adjacent each of the flap valves.

The relief ramp construction of angular surface or curved surface adjacent each of the flap valves formed on the diaphragm providing gradual pressure relief for the adjacent regions of the gasket avoid any tendency for compressive pressures or stresses to distort the flaps. The relief surface construction assures that the valves will seat properly at all times during their operation.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

We claim:

1. In combination, pumping means for pumping liquid hydrocarbon fuels including a pair of members, a cavity formed in one of said members, a pumping diaphragm of flexible nonmetallic material extending across the cavity forming a fuel receiving chamber, said diaphragm being adapted to be exed to establish pumping impulses in said fuel receiving chamber, a port for said fuel receiving chamber, valve means integrally formed on the diaphragm for said port, a flat valve seat formed on one of the members arranged for cooperation with the valve means for controlling the flow of fuel through the port, a recess formed in the other of said members adjacent the valve means to accommodate movement of said valve means to open position, means for securing the members and said diaphragm in fixed relation, a wall region of said recess adjacent the integral connection of the valve means with the diaphragm progressively receding from the plane of the diaphragm to relieve pressure of the member securing means on the valve means.

2. In combination, pumping means for pumping liquid hydrocarbon fuels including a pair of members, one of said members being formed with a cavity, a pumping diaphragm of flexible nonmetallic material extending across the cavity to form a fuel receiving chamber, said diaphragm adapted to be flexed to establish pumping impulses in said fuel receiving chamber, inlet and outlet ports for said fuel receiving chamber, flap valve means inegrally formed on the diaphragm for each of the ports, flat valve seats and recesses provided on the members respectively and arranged for cooperation with the, valve means for controlling the flow of liquid fuel through the inlet and outlet ports, means for securing the members and said diaphragm in fixed relation, a wall region of each recess adjacent the integral connection of the ap valve means with the diaphragm progressively receding from the plane of the diaphragm to relieve pressure of the -member securing means on the flap valve means.

3. In combination, pumping means for pumping liquid hydrocarbon fuels including a pair of members, each of said members being formed with a recess, a pumping diaphragm of flexible nonmetallic material extending across the recesses to form a pumping chamber and a fuel receiving chamber, said diaphragm adapted to be exed by varying fluid pressure in the pumping chamber to establish pumping impulses in said fuel receiving chamber, inlet and outlet ports for said fuel receiving chamber, liap valve means integrally formed on the diaphragm for each of the ports, liat valve seats formed on one of the members arranged for cooperation with the valve means for controlling the flow of liquid fuel through the inlet and outlet ports, a recess adjacent each valve means formed in the other of said members to accommodate movement of said valve means to open positions, means for securing the chambers and said diaphragm in fixed relation, a wall region of each of said recesses adjacent the integral connection of the flap valve means with the diaphragm progressively receding from the plane of the diaphragm to relieve pressure of the member securing means on the valve means.

4. In combination, pumping means for pumping liquid hydrocarbon fuels including a pair of members, each of the members being formed with planar surfaces and a cavity, a pumping diaphragm of flexible nonmetallic material disposed between the planar surfaces of the members, one of said cavities forming with the diaphragm a pumping chamber and with the other a fuel receiving chamber, inlet and outlet ports for said fuel receiving chamber, valve means for said ports, at least one of said valve means comprising a flap portion hingedly joined with the `diaphragm and adapted in closed position to engage a planar surface of one of said members, a recess having a bottom surface formed in the other of said members to accommodate flexing movements of the ap valve, means for securing the members and diaphragm in assembled relation whereby portions of the diaphragm are subjected to pressure `of the securing means, and a curved ramp surface joining the bottom surface of the recess and a planar surface of the member containing the recess at the hinge region of the flap valve for relieving the flap valve from the pressure set up by the securing means.

5. In combination, pumping means for pumping liquid hydrocarbon fuels including a pair of members, each of t-he members being formed with planar surfaces and a cavity, a pumping diaphragm of flexible material disposed between the planar surfaces of the members, one of said cavities forming with the diaphragm a pumping chamber and with the other a fuel receiving chamber, inlet and outlet ports for said fuel receiving chamber, "valve means `for said ports, at least one of said valve means comprising a ap portion hingedly joined with the diaphragm and adapted in closed position to engage a planar surface of one of said members, a recess having a bottom surface formed in the other of said members to accommodate flexing movements of the flap valve, a gasket engaging one of said members having a portion extending into the recess, means for securing the members, gasket and diaphragm in assembled relation whereby portions of the gasket and diaphragm are subjected to pressure of the securing means, and an inclined ramp surface joining the bottom surface of the recess and a planar surface of the member containing the recess at the hinge region of the liap valve for relieving the portion of the gasket extending into the recess and the flap valve from the pressure set up by the secu-ring means.

6. In combination, pumping means for delivering liquid fuel to a charge forming apparatus including a pair of disc-like members having planar surface areas, a pumping diaphragm formed of flexible nonmetallic material disposed between the planar surface areas of said members, means securing said members and diaphragm in fixed relation, concave recesses formed in said members and providing with said diaphragm a pumping chamber and a fuel receiving chamber, a duct in one of said members opening into the pumping chamber and adapted to be connected with a source of varying fluid pressure for vibrating said diaphragm to establish a pumping action, inlet and outlet ports formed in the other of said members for conveying liquid fuel into and away from the fuel receiving chamber, iiap valves for each of said ports iformed integrally with the diaphragm, recesses for-med in one of said members adjacent each flap valve to accommodate opening movements of the valves, and progressively receding transition surfaces forming portions of the walls of the recesses arranged adjacent the integral connection of each flap valve with the diaphragm to relieve pressure of the securing means upon the ap valves.

7. In combination, pumping means for delivering liquid fuel to a charge forming apparatus including a pair of disc-like members having planar surface areas, a pumping diaphragm Aformed of flexible nonmetallic material disposed between the planar surface areas of said members, means securing said members and diaphragm in iixed relation, concave recesses formed in said members and providing with said diaphragm a pumping chamber and a fuel receiving chamber, a duct in one of said members opening into the pumping chamber and adapted to be connected with a source of varying iluid pressure for vibrating said diaphragm to establish a pumping action, inlet and outlet ports formed in the lother of said members for conveying liquid fuel into and away yfrom the fuel receiving chamber, flap valves for each of said ports formed integrally with the diaphragm, recesses formed in one of said members adjacent each flap valve to accommodate iopening movements of the valves, and inclined transition surfaces forming portions of the Walls defining the recesses arranged adjacent the integral connection of each flap valve with the diaphragm to relieve pressure of the securing means upon the lap valves.

8. In combination, pumping means Ifor pumping liquid hydrocarbon fuels including a pair vof members being `formed with -a cavity, a pumping diaphragm disposed between the members and forming with the cavity a pumping chamber and a fuel receiving chamber, a gasket positioned between the diaphragm and one of the members, passage in one of the members opening into the pumping chamber adapted to be connected with a source of varying fluid pressure for actuating the diaphragm, inlet and outlet ports for said fuel receiving chamber, a flap valve for each port integrally lformed on the diaphragm and adapted in port-closing position to engage a planar surface region on one of said members, the other of said members being f'ormed with a recess having a planar bottom surface adjacent each of said ap valves to accommodate opening movements of said valves, means for securing said members, gasket and diaphragm in assembled relation whereby portions of the gasket and diaphragm are subjected to compressive pressure of the securing means, a ramp surface joining the planar bottom surface of each recess with a planar surface of the member, each ramp surface being inclined at an acute angle with respect to the planar surface, said gasket having portions extending into the recesses adjacent -said ramp surfaces, said ramp surfaces being disposed adjacent the regions |of the integral connections of the ap valves with the diaphragm for relieving the extending portions of the gasket and flap valves lof the compression stresses set up by the securing means.

9. In combination, pumping means for pumping liquid hydrocarbon fuels including a pair of members being formed with a cavity, a pumping `diaphragm disposed between the members and forming with the cavity a pumping chamber and a fuel receiving chamber, a gasket positioned between the diaphragm and `one `of said members, passage in one of the members opening into the pumping chamber adapted to be connected with a source of varying fluid pressure for actuating the diaphragm, inlet and outlet ports for said fuel receiving chamber, a flap valve for each port integrally formed lon the diaphragm and adapted in port-closing position to engage planar surface regions on one of said members, the `other of said members being formed with a recess having a planar bottom surface adjacent each of said flap valves to accommodate opening movements of said valves, means for securing said members, gasket and diaphragm in assembled relation whereby portions of the gasket and diaphragm are subjected to compressive pressure of the securing means, a curved ramp surface joining the planar bottom surface of each recess with a planar surface of the member, said gasket having portions extending into the recesses adjacent said curved ramp surfaces, said curved ramp -surfaces being disposed adjacent the regions of the integral connections of the flap valves with the diaphragm for relieving the extending portions of the gasket and flap valves of the compression stresses set up by the securing means.

References Cited in the tile of this patent UNITED STATES PATENTS 1,416,771 Babson et al. May 23, 1922 2,302,447 King et al. Nov. 17, 1942 2,796,838 Phillips June 25, 1957 FOREIGN PATENTS 500,265 Belgium Ian. 15, 1951 

